Author ORCID Identifier

Date Available


Year of Publication


Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation


Agriculture, Food and Environment



First Advisor

Dr. Subba Reddy Palli


RNA interference (RNAi) mechanism is found in many eukaryotes and animal cells, with its endogenous functions as defense against transposable elements and viruses, as well as post transcriptional regulation of gene expression. Since its first discovery, RNAi has contributed enormously as a reverse genetic tool for functional genomic studies. In application, RNAi is used in therapeutics, as well as agricultural crop and livestock protection. Yet, for the wider application of RNAi, improvement of its potency and delivery technologies is needed. Deeper mechanistic understanding of every step of RNAi, from cellular uptake of RNAi trigger molecule to targeted mRNA degradation is key for developing efficient strategy to improve RNAi technology. Insects provide an excellent model to study the mechanism of RNAi due to species specific variation of RNAi efficiency. This allows us to perform comparative studies on different insect species with different RNAi sensitivity. Fall armyworm is notorious for having insensitivity to externally introduced RNAi trigger, such as double stranded RNA (dsRNA). I studied factors that are responsible for its insensitivity to RNAi. I show that stability of dsRNA in extracellular environment and efficient delivery into cells are indeed key factors that must be improved for more efficient RNAi response. With this knowledge in mind, I engineered fall armyworm to improve RNAi efficiency. Colorado potato beetle is known for having highly efficient RNAi response. I studied factors that are responsible for its exceptionally high sensitivity of RNAi. I show that proper intracellular trafficking of dsRNA, especially in and out of endoplasmic reticulum is crucial for highly sensitive RNAi. These findings can lead to the development of better strategies to improve RNAi and widen its application to other agriculturally and medically important insects.

Digital Object Identifier (DOI)